Fluent config sample that outputs logs to stdout, S3 and Cloudwatch Logs

docker-compose.yml

---
version: '3.5'
services:
  fluentd:
    build:
      context: .
      dockerfile: docker/fluentd/Dockerfile
      target: base
    ports:
      - ${DOCKER_HOST_FLUENTD_PORT:-24224}:24224
      - ${DOCKER_HOST_FLUENTD_PORT:-24224}:24224/udp
    volumes:
      - ./docker/fluentd/fluent.conf:/fluentd/etc/fluent.conf:ro
    environment:
      AWS_REGION: ${FLUENTD_AWS_REGION:-}
      AWS_ACCESS_KEY_ID: ${FLUENTD_AWS_ACCESS_KEY_ID:-}
      AWS_SECRET_ACCESS_KEY: ${FLUENTD_AWS_SECRET_ACCESS_KEY:-}

Dockerfile

# for development
FROM fluent/fluentd as base

RUN gem install fluent-plugin-s3 -v 1.1.10 --no-document
RUN gem install fluent-plugin-cloudwatch-logs -v 0.7.3 --no-document


# for production
FROM base AS bundle

COPY docker/fluentd/fluent.conf /fluentd/etc/fluent.conf

fluent.conf

<source>
  @type forward
  @label @applog
  port 24224
  bind 0.0.0.0
</source>

<label @applog>
  <match lograge.*>
    @type copy

    <store>
      @type stdout
    </store>

    <store>
      @type s3

      aws_key_id "#{ENV['AWS_ACCESS_KEY_ID']}"
      aws_sec_key "#{ENV['AWS_SECRET_ACCESS_KEY']}"
      s3_region "#{ENV['AWS_REGION']}"
      s3_bucket fluentd-test
      path app/lograge/%Y-%m-%d/
      s3_object_key_format %{path}%{index}.%{file_extension}
      time_slice_format %Y/%m/%d

      <format>
        @type json
      </format>

      <buffer time>
        @type file
        path /tmp
        timekey 1m
        timekey_wait 0
      </buffer>
    </store>

    <store>
      @type cloudwatch_logs
      log_group_name fluentd-test
      log_stream_name fluentd-test
      auto_create_stream true
    </store>
  </match>
</label>